Re: [libvirt] [PATCH 10/11] Improve SCSI volume key and name generation

The SCSI volumes currently get a name like '17:0:0:1' based on $host:$bus:$target:$lun. The names are intended to be unique per pool and stable across pool restarts. The inclusion of the $host component breaks this, because the $host number for iSCSI pools is dynamically allocated by the kernel at time of login. This changes the name to be 'unit:0:0:1', ie removes the leading host component. THe 'unit:' prefix is just to ensure the volume

name doesn't start with a number and make it clearer when seen out of context. The SCSI volumes also get a 'key' field based on the fully qualified volume path. All SCSI volumes have a unique serial available in hardware which can be obtained by sending a suitable SCSI command. Call out to udev's 'scsi_id' command to fetch this value

* src/storage/storage_backend_scsi.c: Improve key and name field value stability and uniqness

+static char * +virStorageBackendSCSISerial(const char *dev) +{ + const char *cmdargv[] = { + "/lib/udev/scsi_id", + "--replace-whitespace", + "--whitelisted", + "--device", dev, + NULL + }; + int fd = -1; + pid_t child; + FILE *list = NULL; + char line[1024]; + char *serial = NULL; + int err; + int exitstatus; + + /* Run the program and capture its output */ + if (virExec(cmdargv, NULL, NULL, + &child, -1, &fd, NULL, VIR_EXEC_NONE) < 0) + goto cleanup;

+ + if ((list = fdopen(fd, "r")) == NULL) {

static int virStorageBackendSCSINewLun(virStoragePoolObjPtr pool, - uint32_t host, + uint32_t host ATTRIBUTE_UNUSED, uint32_t bus, uint32_t target, uint32_t lun, @@ -183,7 +240,12 @@ virStorageBackendSCSINewLun(virStoragePoolObjPtr pool, vol->type = VIR_STORAGE_VOL_BLOCK; - if (virAsprintf(&(vol->name), "%u.%u.%u.%u", host, bus, target, lun) < 0) { + /* 'host' is dynamically allocated by the kernel, first come, + * first served, per HBA. As such it isn't suitable for use + * in the volume name. We only need uniquness per-pool, so